Upconversion mechanisms and thermal effects of Er3+ in Er3+ doped yttria nanocrystals

Efficient Er3+:Y2O3 phosphor is synthesized by the sol–gel method. Rate equations for Er3+ energy level populations are used to investigate pump power and temperature dependences of upconversion intensity as well as the fluorescence decay profiles. Excited state absorption cross section of Er3+ 4I13/2 of 6.8×10−27 m2 and cross relaxation rate of 6200 s−1 are determined from comparison between theoretical predictions and experimental data. In addition, it is found that effect of temperature on the phonon-assistant absorption cannot be neglected. This work provides references for the prediction of the upconversion behavior in Er3+ singly doped matrix.